树的遍历

一.已知后序中序求先序

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
string ZX,HX;
void Search(string a,string b){
	int len=a.size();
	if(len==1){cout<<a[0];return;}
	char GenJieDian=b[len-1];b.substr(0,len-1);
	cout<<GenJieDian;
	int p=a.find(GenJieDian,0);                             //find(a,b)== find 'a' from b to INF
	if(p)Search(a.substr(0,p),b.substr(0,p));
	if(p<len-1)Search(a.substr(p+1,len-p-1),b.substr(p,len-p-1));
	return;
}
int main(){
	freopen("xianxu.in","r",stdin);
	freopen("xianxu.out","w",stdout);
	cin>>ZX>>HX;Search(ZX,HX);
}

　　

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二.已知先序中序求后序

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
string ZX,HX;
void Search(string a,string b){
	int len=a.size();
	if(len==1){cout<<a[0];return;}
	char GenJieDian=a[0];a=a.substr(1,len-1);
	int p=b.find(GenJieDian,0);                             //find(a,b)== find 'a' from b to INF
	if(p)Search(a.substr(0,p),b.substr(0,p));
	if(p<len-1)Search(a.substr(p,len-p-1),b.substr(p+1,len-p-1));
	cout<<GenJieDian;
	return;
}
int main(){
	freopen("houxu.in","r",stdin);
	freopen("houxu.out","w",stdout);
	cin>>ZX>>HX;Search(ZX,HX);
}

 

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三.多叉树转二叉树

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
struct list
{
    int l;
    int r;
}node[2001];
void init()
{
    int i;
    scanf("%d%d",&n,&m);
    memset(vis,-1,sizeof(vis));
    for(i=0;i<=n;i++)
    {
        node[i].l=node[i].r=0;
    }
    for(i=1;i<=n;i++)//边输入，边转化
    {
        int a,b;
        scanf("%d%d",&a,&b);
        node[b].r=node[a].l;
        node[a].l=b;
    }
}
int main()
{
    init();
    return 0;
}